Human nutrition. Clinical nutrition最新文献

A longitudinal study of rural Hyderabad children has been in progress from 1965. About 700 boys who are under follow-up are now in late adolescence and young adult stage. Of them, 410 had completed linear growth by the 1983-84 annual round. Severe growth retardation was observed among one-sixth at their 5th year of life. The severely undernourished group grew up as the shortest and lightest young adults. One-fifth of the boys under study worked for wages in their childhood. Their work experience ranged from 4 to 8 years at 14 years of age (child labourers or working children). Growth and development of working children was compared with students, who were matched for nutritional status at age 5. Working children lost considerable ground and suffered significant growth deficits.

Since the time of Lavoisier it has been known that the ingestion of food in animals and man produces an increase in oxygen consumption. This increase in metabolic rate was originally called 'specific dynamic action' (SDA) and is now widely referred to as the thermic effect (TE) of food or diet-induced thermogenesis (DIT) (Rothwell & Stock, 1981). Much of the early work on the thermic effect was confined to the type and amount of food, notably the macronutrients--proteins, fats and carbohydrates. Later, it was shown that certain minor constituents of the diet such as caffeine and associated methylxanthines (Zahorska-Markrewicz, 1980; Jung et al., 1981) in tea and coffee could also have a profound effect on metabolic rate. The consumption of alcohol was also shown to increase metabolic rate (Rosenberg & Durnin, 1978). The work described in this paper reports the effect of another minor constituent of food, spices, on metabolic rate. Although the use of spices in our food has steadily increased with time little information exists on their effect on the metabolic rate. It has been estimated that approximately 40 different spices are used in our diet today. This communication reports the effect of chilli (red pepper, capsicum annuum) and mustard (Brassica juncea).

The Fifth World Food Survey (FAO, 1986) has defined energy malnutrition as an intake below maintenance requirement and has suggested that maintenance requirement is equal to 1.4 times the resting metabolic rate (RMR), or, alternatively, 1.4 X RMR minus twice the standard deviation of the variation between normal subjects. In order to give substance to these numbers, we have measured the 24-h energy expenditure on two different physical activity programmes. The measurements were made on 38 men and 18 women, all apparently healthy and weighing about 65 kg. The measurements were performed at 24 degrees C and ambient humidity and the subjects wore clothes such as to be within the thermal comfort range. Measurements of the RMR were also performed. In one of the programmes, the average value of the 24-h energy expenditure divided by the RMR was found to be identical in men and women and equal to 1.38 X RMR. In another programme, with more intense physical activity, the corresponding number was 1.53 X RMR. In all three series of measurements, the coefficient of variation between subjects was found to be the same, ie between 6 and 8 per cent.

Riboflavin and vitamin B6 status of mothers from a low-income group were assessed by erythrocyte glutathione reductase activation and erythrocyte aspartate aminotransferase activation tests respectively, at different stages of lactation. Levels of these vitamins in milk were also measured. The majority of the women had biochemical evidence of vitamins B2 and B6 deficiency. There was a bizarre reduction in erythrocyte glutathione reductase activation from 6 to 30 d post partum. Levels of riboflavin in milk were in general satisfactory, but vitamin B6 levels were lower than the values reported from developed countries. Clear-cut correlations between the enzymatic indices of vitamin status evaluation and milk levels of the corresponding vitamins were not apparent.

Modified building blocks are found in rRNA, tRNA and mRNA. Apart from pseudouridine these are mostly base- or ribose-methylated nucleosides. If these compounds are neither recycled nor degraded, they should be quantitatively excreted. For pseudouridine (Weissman et al., 1962; Dugaiczyk & Eiler, 1966) and 7-methylguanine (Craddock, Mattocks & Magee, 1968), urinary excretion has been shown to be quantitative. Since the turnover rates of rRNA and tRNA, which contain most of the modified nucleosides, are similar within a given tissue, compounds found only in these two classes of RNA should appear in urine in approximately the proportions in which they are present in the body. Using pseudouridine as internal standard, we show this indeed to be likely for one of the major RNA catabolites in human urine, N2,N2-dimethylguanosine, a compound present only in tRNA. By contrast, 7-methylguanine is excreted in threefold larger amounts than can be explained by joint provenance from tRNA and rRNA only; the remainder we assume to come from the 'cap' structure of mRNA, known for its high turnover. We suggest that one can use the urinary excretion of pseudouridine, N2,N2-dimethylguan(os)ine and 7-methylguanine to assess the whole-body turnover rates in man of rRNA, tRNA and mRNA, respectively. Such data may be useful to define whole-body metabolic activity.

Dietary calcium intake in relation to calcium status in rural black South African children was investigated. Fifteen subjects in each age group, 3-5 years, 8-10 years, 13-16 years with lowered serum calcium (less than 2.25 mmol/l) and raised serum alkaline phosphatase (greater than 300 i.u./l) were matched with controls having normal serum biochemistry. A dietary interview and 24-h recall was conducted with each subject; nutrient value of the diet was calculated from standard food tables. At 3-5 years, although the study group had significantly lower calcium intakes, there was no significant relationship between dietary calcium intake and calcium status. Study children in the age groups 8-10 years and 13-16 years had significantly lower dietary calcium intakes than controls and dietary calcium intake showed significant correlation with serum calcium levels, serum alkaline phosphatase levels, bone mineral density, metacarpal cortical thickness and calcium excretion. Thus it appears that low dietary calcium intakes may be reflected by hypocalcaemia, elevated alkaline phosphatase and decreased bone mineral content in pre-adolescent children.

The changes in buffy layer (BL) vitamin C concentration following surgical operations were studied in relation to changes in the leucocyte and platelet counts. It was found that the postoperative fall and subsequent changes in BL vitamin C concentration corresponded to changes in the platelet/leucocyte ratio (PLR) in whole blood and consequently in the buffy layer preparations from which vitamin C concentrations were measured. The results of the study showed that the fall in BL vitamin C measured following operations is an artifact of the method used rather than a demand for vitamin C. It highlights the importance of measuring the PLR, and suggests the need for a differential leucocyte count, when undertaking BL vitamin C analysis.